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WEEK 4

TOPIC: HALOGENS

CONTENT:

  1. Electronic configuration of halogens, physical properties of halogens and gradation down the group.
  2. Chemical properties of halogens and gradation down the group
  3. Uses of halogens and their compounds.

PERIOD 1 AND 2: ELECTRONIC CONFIGURATION OF HALOGENS

Halogens are found in group (viii) of the periodic table and consist of fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I) and Astatine (At).

The name halogen is of Greek origin meaning salt formers because they readily form salts from metals. Halogens are very reactive non- metals with remarkable similarities in properties. This is because each halogen atom has seven only one electron to attain the octet. They are strong oxidizing agents with varying oxidation Numbers. The halogens are highly electro negative elements. The halogens share electrons to form covalent compounds or accept electrons to form ionic compounds. It is the electronic configuration of halogens that accounts for their electronegative nature, oxidising ability and the fact that they form mainly single covalent bonds.

ELECTRO CONFIGURATION AND SOME PROPERTIES OF THE HALOGENS AND GRADATION OF THE PROPERTIES

Element

 

Atomic

Number

Electronic configuration

 

Atomic radius Ionic radius Electro-negativity Electro-affinity  Atomic

Mass

Fluorine [F] 9 [2,7]

1S22S22P5

0.072 0.136 4.0 -3.35 19.0
Chlorine [Cl] 17 [2,8,7]

1S22S2 2p63S23P5

 

-0.099 0.181 3.0 -3.61 35.5

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